Inclosed electric fuse.



R. 0-. com. INCLOS ED ELECTRIC FUSE.

APPLICATION FILED MAR. 28. IQIB;

Patented Aug. 27, 1918.

v IN VEN TOR.

A TTORNEY.

UNITED STATES PATENT OFFICE.

ROBERT 0. Com, or HARTFORD, CONNECTICUT, ASSIGNOR' 'ro THE Jesus-PRA T COM- PANY, 0F HARTFORD, CONNECTICUT, AQORPOBATION or CONNECTICUT.

' INCLOSED ELECTRIC FUSE.

Specification of Letters Patent. I Patented Aug; 27, 1918.

Application filed March 28, 1918. Serial No. 225,177.

To all whom it may concern:

Be it known thatI, ROBERT C. COLE, a

citizen of the United States, residing at fuses of. the cartridge type, that is, those fuses which have insulating tubes with metal end caps, links of fusible metal with terminals extending through the end caps, and granular vapor-condensing andabsorb ing material filling the interior about the These fuses are safetydevices and. are made to operateaccurately,consequently it is considered very desirable that they be constructed so that they cannot berefilled by everybody after they have been blown, and thus eliminate the possibility of: the insertion of links of non-fusible wireior of fusible wire that is of greater capacity than the rating of the fuses or is safe for the circuits in which the fuses are to be used, by an unskilled person, which would render the fuses elements of danger rather than safety devices. It is, however, sometimes advantageous to have these fuses constructed so that while they cannot be readily refilled by unskilled persons they may be refilled by the manufacturer in order that all of the parts of a large quantity of blown fuses may not have to be thrown away. It is necessary in order to attain accuracy that not only the fuse links be of correctcarrying capacity, but that their terminals be solidly joined to the end caps, and furthermore it is necessary that the end caps be securely attached to the insulating tubes so that they will not be blown off by the pressure of the gas generated when the fuses are blown and the metal of the links changes from a solid to a vaporous state.

The object ofthis invention is to provide what may be termed a semi-refillable fuse, that is, a fuse of this nature which, while not readily refillable by the ordinary individual, can be cheaply refilled by the manufacturer.

This object is attained by securing the metallic end caps to the ends of the insulating tube so that they cannot be taken off and forming these end caps in a way that enables the granular material to be easily filled into the tube and the. terminals of the fusible link and of an indicator wire, if used,

to. be quickly located and easily soldered to the caps in suchmanner that when it is desired to refill the. tube: after the linkhas been blownthe end cap'scan be opened and a new link, a proper indicator wire and fresh filling material can. be substituted without destroying anyof the formed parts.

Figure l of the accompanying drawing is a view onenlarged scale of a fuse embodying this invention showing it in condition to be filled} Fig. 2 is a similar view showedges 3 of the caps are crimped into the body of the tube so that the caps cannot be removed after having once been fixed in place. These caps have perforated reentrant outer ends, that is, their ends are provided with inwardly extending cup-shaped recesses 4 with openings 5 of substantial size through the bottom of the cups. The fusible link may be made in the ordinary way of the usual material. This link is shown in the drawings as extending through the tube and as having its terminals passing through the openings into the cups in the end caps. Thin metallic cup-shaped plates 7 are set in the openings in the bottoms of the cupshaped recesses in the end caps. These cups are perforated with openings that just fit the terminals of the link. Before the plates are placed in position the case is filled with granular insulating material 8 for condensing and absorbing the gases generated by the melting of the link when the fuse is blown. After the plates have been inserted in the recesses in the end caps with the terminals of the link extending through them, the recesses are filled flush with solder 9 and the ends smoothed off so that the ends will be flat to form a desirable finish and also enable them to make proper contact with the terminals of a plug when it is desired to use the fuse therein. The melted and makes a firm and substantial metallic joint and close electrical connection between the link terminals and the end caps.

The metallic cap may have small tongues 10 struck outward from the material of its ends to form a cleat about which the end of a fine indicating wire, if used, may be rove to retain it until the link and cap are soldered, and a notch 11 may be made in the edge of the opening through the cap for the passage of such indicating wire.

The end caps are first placed upon and permanently secured to the tube and one end closed with the link terminal, plate and cap soldered together. The filling material is then inserted through the opening in the other end cap and after the tube is filled the plate is placed in this cap at this end and the solder poured in. This fuse is not readily renewed by the ordinary individual, but the manufacturer receiving a large number of blown fuses, may simply melt the solder from the recesses in the end caps and knock out the plates when thus freed. The remains of the melted fuse link and the filling material may then be shaken out through the openings in the end caps. After the tubes have been cleaned in this way a new link may be inserted, fresh filling may be poured in and the end caps again closed by inserting the plates and resoldering them in place.

The invention claimed is;

1. A11 inclosed electric fuse comprising an insulating tubular case, metallic caps permanently fastened on theends of the case, said caps having reentrant perforated outer ends, perforated metallic plates located in the bottom of the recesses in said caps, a fusible link with terminals extending through the perforations in said plates, granular absorbing and condensing material filling the case, and solder filling the recesses in the end caps and mechanically and elecrically uniting the link terminals, plates and caps.

2. An inclosed electric fuse comprising an insulating tubular case, metallic caps permanently fastened on the end of the case, said caps having recntrant perforated outer ends and portions of their ends struck out to form a cleat, perforated metallic plates located in the bottom of the recesses in said caps, a fusible link with terminals extending through the perforations in said 7 ROBERT C. COLE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Intent; Washington, D. 0." 

